I can fix most machines due to having the ability to look at what it does and immediately have a good idea how it does it - a talent I must have inherited from my father, who was a very gifted engineer.

Printers, however... Printers have at least ten billion components, many of which are merely a few atoms in size and are made of soft cheese instead of hard plastic or metal. They were also designed by M.C. Escher, Salvador Dali and H.R. Giger one day after they'd each dropped about five tabs of acid, are home to numerous nanopoltergeists which will move various components around every time you blink and have been re-engineered several times over by Motie Watchmakers (one for the Pournelle and Niven fans there).

So, big respect for making yours work.